| Autor: |
Williams, Berry L, Burns, Stephen J, Scroxton, Nick, Godfrey, Laurie R, Tiger, Benjamin H, Yellen, Brian, Dawson, Robin R, Faina, Peterson, McGee, David, Ranivoharimanana, Lovasoa |
| Předmět: |
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| Zdroj: |
Holocene; May2024, Vol. 34 Issue 5, p593-603, 11p |
| Abstrakt: |
We present a continuous high-resolution precisely dated multiproxy record of hydroclimate variability at Anjohibe cave in northwestern Madagascar using speleothem AB13. The record spans from ~4484 y BP to ~2863 y BP. Stalagmite δ18O, δ13C and Sr/Ca ratios show very similar changes in hydroclimate. The mechanism controlling Sr/Ca changes, however, from prior calcite precipitation to degree of dolomite dissolution at about 4 ky BP. Our record is also in good agreement with previously published speleothem records from the same area. This agreement and multiproxy consensus indicate that AB13 provides a robust record of hydroclimate variability, including a continuous record of hydroclimate variability across the 4.2 ka event. This 4.2 ka event in Madagascar is marked by two distinct periods of drying between ~3900 y BP to 4300 y BP. A dry 4.2 ka event at this Southern Hemisphere site helps limit possible mechanisms for the event, indicating that a meridional shift to the south in the ITCZ is not responsible for the 4.2 ka event. In addition, the 4.2 ka event does not stand out as a unique dry period in our record. The longest and driest period of the record lasted ~300 years with peak dryness at ~3000 y BP. Our record differs significantly from a speleothem record from Rodrigues Island, located ~1800 km to the east of our study area in Madagascar suggesting different climatological controls on northwest Madagascar and more oceanic sites to the east. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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